Development of a digital spectrometric system for material studying by positron annihilation techniques

Positron annihilation spectroscopy techniques are sensitive laboratory methods of in-depth study of the material structure and processes occurring in it. The digital spectrometric system described in this paper is designed to study the defect structure of materials by positron annihilation spectroscopy techniques. This system combines the methods of positron annihilation lifetime spectroscopy and Doppler broadening spectroscopy. These two techniques can be implemented either in one complex or individually. Application of these experimental techniques simultaneously provides a temporal and energy distribution of annihilation gamma-quanta, i.e. the most comprehensive qualitative and quantitative information of the electronic structure of the substance can be obtained. Using the coincidence γ-γ measurements in the Dopler broadening spectroscopy technique also allows observing the high-momentum part of the spectrum of the annihilation of positrons with deep shell electrons. The analysis of this part of spectrum enables to obtain the information about the chemical composition of the material. In comparison with the traditional analog systems, this system is being developed using modern digital components to ensure the ease of setup and operation of the equipment, as well as enabling the development of the system in order to improve its characteristics.